Techniques have been developed to localize and quantitate biologic tumor markers in the cells and sera of patients with urologic cancers. These markers include human chorionic gonadotropin, alpha-fetoprotein, pregnancy specific beta 1 glycoprotein (SP1), different isoenzymes of lactic dehydrogenase (LDH), ABO(H) antigens, and steroid receptors. These markers have been correlated with the histology, grade, stage, and management of patients with urologic cancers. Experimental animal models of cancer induction for the kidney, bladder, prostate, and testis have also been developed. These animal models are being utilized to study the role of cytoreductive surgery, chemotherapy, and immunotherapy of these urologic cancers. Athymic mice have been utilized for xenograft of testicular tumor that produces markers. By utilizing specific antibody labeled with a gamma-emitting radioisotope such as 131I, the role of radioimmunodetection and radioimmunotherapy is being investigated in testicular and prostatic cancer.